This invention relates to a water jet propelling vessel and more particularly to an improved arrangement for mounting and operating the jet propulsion unit of such a vessel.
One popular form of watercraft is that of the jet propulsion type. This type of watercraft generally has a hull that is formed with a longitudinally extending tunnel in the rear portion of the hull. A jet propulsion unit, consisting of an outer housing that defines a water inlet, an impeller housing in which an impeller is supported and a dischage nozzle are supported within the tunnel. The impeller is driven by an engine that is positioned forwardly in the watercraft by means of an impeller shaft that extends through the tunnel to the jet propulsion unit. Although this type of vessel has a number of advantages, the mounting of the jet propulsion unit rearwardly of the driving engine can present some difficulties.
One particular problem with this type of unit is that the water inlet and housing in which the impeller casing are formed are a unitary assembly that must be removed as such when the propulsion unit is being serviced. As a result, this necessitates removal of the water intake duct every time the propulsion unit is serviced. Of course, it is desirable to insure that the intake duct is adequately sealed around the tunnel area so that water cannot inadvertently pass into the tunnel rather than through the inlet and also to avoid any leakage in this area. The flow resistance of such an arrangement would be unacceptable and, furthermore, the efficiency of the total unit may be adversely affected. In addition, the prior art types of arrangements can cause distortion or damage to the watercraft hull or inlet duct upon assembly and disassembly.
It is, therefore, a principal object of this invention to provide an improved water jet propelling vessel and an arrangement for mounting and driving the jet propulsion unit in the hull of the watercraft.
It is a further object of this invention to provide an improved hull arrangement and cooperating jet propulsion unit for a water vessel of this type.